Service-meter circuit for telephone systems.



F. ALDENDORFF.

SERVICE METER CIRCUIT FOR TELEPHONE SYSTEMS.

APPLICATION FILED on. 3. 1913.

1 175,579. Patented Mar. 14:, 1916.

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SERVICE METER CIRCUIT FOR TELEPHONE SYSTEMS.

APPLICATION FILED OCT- 3. I9I3.

1, 175,579, Patented Mar. 14,1916. 7

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SERVICE METER cmcun FOR TELEPHONE SYSTEMS. APPLICATIVON FILED OCT. 3'. 1913.

l 175,579. Patented Mar. 14;, 1916.

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F.ALDENDORFF. SERVICE METER CIRCUIT FOR TELEPHONE SYSTEMS. APPLICATION FILED OCT- 3,1913.

15175.,579. Patented Mar. 14, 1916.

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starts a FRITZ ALDENDOREF, OF ANTWEB-P, BELGIUM, ASSIG-NOR, BY MESNE ASSIGNMENTS, T0 WESTERN ELECTRIC COMPANY, INCORPORATED, A COR-PQRATIGN OF NEW YORK.

I SERVICE-METER CIRCUIT FOR TELEPHONE SYSTEMS.

Application filed October 3,

1 0 all whom it may concern:

Be it known that I, FRITZ ALnENDonrr, a subject of the King of Great Britain, resid ing at 59 Rue Vouw, Mortsel, Antwerp, Belgium, have invented a Service-Meter Circuit for Telephone Systems, of which the following is a true, clear, concise, and exact description.

My invention relates to telephone systems and has to do more particularly with service meter circuits for automatic telephone exchanges.

According to my invention the service meter circuits are so arranged that a call made by a station is registered when the said station starts to make another call. The meter or register belonging to a calling station is prepared for registering the moment the station calledby the calling station responds. By arranging the system so that a call made by a station is registered when the station starts to make another call, certain advantages are obtained in cases where local connections for instance between two subscribers in a certain city-are interrupted in case one of the subscribers is wantedior a long distance connection to another town. In such cases a local subscriber, who has called and obtained connection with another local subscriber can prevent the connection from being registered by his meter by continuing the conversation with a local subscriber, without having replaced his receiver on the switchhook, after the long distance conversation is finished. For carrying out these ideas, devices are provided, by means of which an operator at a long distance exchange may cause the switches used for connecting two local stations to be restored,

iurther devices being provided whichenable a station to rcstablish a connection that has been disrupted by the intervention of the long distance exchange, and the meter circuits of the station being so arranged that they are independent of any interference from the long distance exchange. In the case of a calling busy station being wanted for a long distance connection, the long distance operator actuates devices associated with the first selector used bythe calling SllbSClll'lGl for the local connection, these devices causing the first selector to be restored to its normal position, but not affecting the Specification of Letters Iatent.

Patented Mar. 14, 1916.. 191s. Serial No. 793,122.

line finder or distributing switch that has made connection between the calling subscriber and the first selector. In case a called busy subscriber is wanted for a long distance connection, the long distance operator disconnects the called busy subscriber from the calling subscriber, without restoring the switches used for the local connection. A signaling device isthen connected to the calling end of the local connection, which may be associated with a phonograph or any kind of code signaling means that intimates to the calling subscriber that the called subscriber has been connected to a long distance line, and will be re-connected to him immediately the long distance conversation is finished. The circuits are so ar ranged that one and the same wire eXtending through the chain of selectors used for establishing a local connection serve for testing, metering and releasing.

The invention is shown in the accompanying drawings, in which I Figurel shows a subscribers station, a long distance switching device and a distributing switch; Fig. 2 shows the first selector; Fig. 3 illustrates the circuit of the second selector; Fig. t shows the circuits of the connector switch, and Fig. 5 shows the synchronous circuit changer used in connection with the selectors. In these only the circuits'and parts essential to the invention are shown, all details unnecessary for a clear understanding of the essential features having been omitted.

In Fig. 1 a subscribers station 100 an a long distance switching oii'ice 104 are represented "as connected to a local exchange by lines 20, 21. and 31, 32, 33, 33 respectively. The subscribers, 100, are each connected to a distributing switch 101, having movable contacts 1, 2, 8, 4' capable of traveling over sets of fixed contacts, each set comprising fourcontacts 5, 6, 7 8 connected to the wires 22, 23, 24:, 25 which comprise a trunk leading to a selector 102, Fig. 2. Each line coming from the long distance oflice 104i" terminates in the local exchange in a selector 103, of which only the movable contacts 34, 35, 36, 400 and a few sets of fixed contacts are shown. Each subscribers line 20, 21 is connected by wires 17, 18, 19. 401 to a set of fixed contacts on selectors 103. Each sub driving magnetsof the selector 102 have been omitted. The first selector is provided with a synchronous circuit changer 50 having a driving magnet 49 which steps around a movable contact arm 51 and the movable contact 52. At each step that the synchronous circuit changer 50 takes, the movable arms 51 and 52 travel a distance equal to that contained between the contacts 53 and 53 respectively, to the next contacts 54, 54. The contact 53 is connected to the negative pole of the battery. Contact 54 is at certain times connected to the negative pole of the battery through n armature contact 878 of a relay 371. The contact arm 52 is not long enough to make connection with the contacts 53 to 54. In traveling from the contacts 53 to 54 and from the contacts 54 to 55 the arm 52 brushes past pairs of contacts 56, 57 and 58, 59. In traveling from 53 to 54, the arm 52 momentarily connects the test brush 43 to a wire 60, which leads to the meter of a connected calling subscriber in a manner that will be described later. In traveling from 54' to 55 the arm 52 momentarily connects the negative pole of the battery to a wire 61 leading to the release magnet 46 of the selector 102, and under certain circumstances causes the selector 102 to be restored to its normal position. The selector has a test relay 48, which controls contacts 62, 63, 64, 65, 66, 67. As long as the relay 48 is deenergized the contacts 62, 63, 64, 65, 67 are open, but when the relay is actuated, the contacts 62, 63, 64, 65 and 67 are closed and contact 66 is opened. Normally relay. 44 and a. resistance 45 are connected through contacts 68, 69 of a relay 47 to the wires 22,

23 leading to a calling subscriber, and by the relay 44 the calling subscriber controls the motor magnets or driving magnets of the first selector 102 and of the second selector 104,'Fig. 3, and the other selectors 105, Fig. 4, used for establishing the connection. These motor magnet controlling circuits are not shown, as they have nothing to do with the invention, and any known kinds of circuits may be used. The relay 47 is controlled from the long distance exchange 104 in the manner to be presently described. All parts of the first selector102 Which have not been mentioned will become clear in reading the description of the operation of the circuits given below. V

In Fig. 3, 104 represents the essential features of a second selector, and in Fig. 4 the essential circuits of a final selector 105 are shown. The second selector 104 has a synchronous circuit changer comprising contact arms 78, 74 and a drivingmagnet 71. The operation of this circuit changer is similar to that described in connection with the first selector. The second selector has a test relay 7 5,. which controls contacts 76, 77, 78, 79, 80, 81, 82 and 83. Normally contacts 76, 78 and 82 are closed, but upon the relay being energized these contacts are opened, and contacts 77, 79, 80, 81 and 83 are closed. 85 and 86 indicate the driving magnets, and 84 the release magnet of the selector. The movable contacts of the selector are represented by 87, 88, 89, which travel over fixed contacts connected to trunks, each trunk being represented by the contact arms 94, and a driving magnet 357. The synchronous circuit changer is similar to that described in connection with the first selector. The final selector is provided with a meter control relay 08 that connects the negative pole of the battery to the pair of contacts 121, 120, whenever a completed call is. to be registered. 97 represents the test relay of the final selector; 123 is a ringing control relay. 124 is a combined cut-01f and line extending relay, which extends the line of the calling subscriber to' that of the wanted subscriber, after the wanted subscriber has responded to a call, and at the same time cuts off the driving magnets 125, 126 of the final selector. The relays 127, 128 are connected to the wanted subscribers line after this subscriber has responded to a call, and form the means by which the wanted subscriber can cause the switches to be restored to normal. The control of these relays is made independent of the calling subscriber by the condensers 129, 130 at the first selector, which prevent current flowing through these relays to the calling subscriber, while they still provide a path for the talking currents between a cal ing and a called subscriber.

In Fig. 5 a synchronous circuit changer of the kind used in connection with the selectors Figs. 2, 8, and 4 is shown. This instrument consists of a ratchet that carries contact arms 151, 149 and is driven by a pawl 152 attached to a lever 153 that turns about a pivot 154, and has an armature 155 capable of being actuated by a magnet 156. On the driving magnet being energized, the armature 155 is attracted, and the pawl 152 iscaused to engage with a new tooth, 157..

A aclied to the lever 153 by a rod 158 is the 91 U011 159 that" reciprocates in a dashpot 160. On the armature 155 being attracted valves 161, 10:2 of the piston 159 open so to prevent the piston 159 from offering great resistance to the movement of the lever 153, so that when the electroinagnet 156 energized this lever actspromptly and allows the pawl 152 to drop quickly behind. a new tooth 157 of the ratchet 150. Upon thesubsequcnt deenergization of the magnet 156, the spring 163 which was stretched upon the energization of the magnet 156 exerts a pull on the lever 153 and causes the pawl 152 to move the ratchet 150 and the contact arms 151, 14:9 attached thereto, through an angle corresponding to the pitch of one tooth 157. This movement of the ratchet will bring the arm 149 from its normal contact 104. to the next contact 165, and the arm, 151 will brush past the pair of contacts 106, 10'1". The movement of the ratchet caused by the spring 163 may be tin'ied by the dashpot 160, so that the contacts 106. 1.0? may be closed for a certain period of time.

The meters 9, 1, used in connection with this system are of a special kind. The counzzing train is moved in the usual manner by ratchet 15, that is stepped forward by a pawl 1% attached to a lever 12, that turns upon a pivot 13. The lower end of the lever 12 extends to another lever 201 that has a catch 20%. The upper end of the lever 12 is attracted so as to move the lever whenever av magnet 10 is energized. The lower end of the lever 12 then moves toward the right. and at its left side the catch 202 attached to the lever 201 rises so as to hold the arm 1 in the position into which it is moved by the attraction oi. the magnet 10. The lever 201 with the catch can. be pulled away from the lower end or lever 12 by a magnet 11. .Vhen this takes place the lever 12 is pulled toward the right by a spring 16, and then the pawl 14, which by the attraction of the lever 19 was caused to drop into a new tooth on the ratchet 15. drives this ratchet fiiirward and cause a new :all to be registered.

Tie (mcraticn of the s stem as follows.ll hen the subscriber 100 raises his receiver from. the hook in order to make the call. a current flows from the negative pole at the battery of the exchange through the right hand winding of the line relay 38. conta ft 300, line L0, subscribefs station 100. line 21. contact 301, left hand winding of line relay 38. back to the positive pole of the battery. The line relay 38 on attracting its armaturcs closes a circuit tor the dr 'ing in e battery through contact 2-303 to the positive pole lree trunk 23. 21-,

3-). which may be traced from the through the driving magnet 39 cause the contact arms 1, 2, 3, to travel step by step from one set of fixed contacts 6, 7, 8 to the next, until a free trunk 22, 21, 25, 1 lg. 2, is found, when a current will flow through the test relay 37 from the negative pole of the battery through contact 30-1, winding 305, movable contact 3, fixed contact 8, wire 25, wire 806, contact 307, resistance 308, positive pole of the battery. Incidentally a circuit is also closed from the negative pole of the battery through 301-, winding 305,

wire 29, magnet 10 of the meter, to the positive pole of the battery. Magnet 10 is, however, so adjusted as to be energized only upon the direct applicathjai of the battery. and will not be energized by a current flow ing through it through the winding 305. Test relay 87 attract its armature and opens the contacts 300, 301 and 309 and closes the contacts 310 311, 312, By opening the contacts 300 and 301, the line relay 38 is deprived oi current, so that the circuit of the driving magnet 39 is opened at contact 802 and the movable contacts 1, 2, 3, 1 are caused. to sto 'r At contacts 310, 311 the calling subscribers line 20, 21 is extended through 1, (f3, and tlu'ough '2, 7, 523 to the first selector 102. By the closure of the contact 312 a part of the winding 305 of the test relay 3? is short circuited so as to cause a drop of potential on the test wire 25, which will prevent any other distributing switch 101 from connecting a calling subscriber to the same first selector 102. At the contacts 313 the negative pole of the battery is connected to the winding 305, so that the test relay 3'? is not deprived e1": current by the deenergization ot' the line relay 38. It is to be noted that immediately the calling subscriber called, a circuit was closed by the line relay 38 through the armature contact 31% from the negative pole of the battery through 31 1, 30., magnet 11, to the positive pole of the battery. By this circuit the magnet 11 was energized until the line relay was deprived. of current through the distributing switch. 101 having found a The electro-magnet 11 was then. deenergized again. energization of the electroina net 11 simply causes the spring catch 302 to he pulled away for a short time from the lower end of the lever 12. By 5 1' ciable effect is prodiu d if the previous call 1nade by the subscriber was an. ineffective nets oi the succeeding selector and conned This function no appre- German patent to Siemens & Halske Akt- Ges. No. 256,288, February 11, 1913. This series of selecting impulses have the effect of causing the movable contacts e1, 12, 13 of the selector to hunt for a trunk leading to an idle selector 10 1. The moment an idle trunk 315, 316, 317' is found, the test.

relay $18 of the selector receives current over the following path :-negative pole of thebattery, contact 53, 51, 48, 66, 13,- 317, re-" sistance 318, positive pole of, the battery. The test relay 18 then closes the contacts 62, 63, c1, and 67 and opens the contact 66. By the closure of the contacts 64, 65 and 67 the driving magnet 19 of the synchronous circuit changer 50 is connected in parallel with the winding of the test relay 7 18. A drop of potential is hereby produced on the test wire 317 and the busy condition of the trunk 315, 316, 317' established. The calling subscriber now sends another series of impulses through the relay 4%, and this has the effect of sending impulses by any known form of motor magnet controllin circuits, through the driving magnet 85 of the second selector 104: and through a change-over relay 86. This will cause the operation of the movable contacts 87, 88 and 89, which will hunt for an idle trunk line 90, 91, 92 leading to a final selector 105 in the group of subscribers in which the wanted line is contained. The moment a free trunk 90, 91 is reached the test relay of the second selector is energized by a current flowing from the negative pole of the battery through contact arm 7 3, relay 75, contacts 82, 89, test 'wire 92, relay 96 to positive pole of the battery. The relay 96 is energized and closes contact 102 and this has the effect of energizing the driving magnet 357 of the synchronous circuit changer 93. The driving magnet 357 receives current from the positive pole of the battery partly through the relay 96 and partly through the resistance 318, through test wires 317 and 92, contact 102, and from here the circuit continues through the magnet 357, contact arm 9%, contact 403 to the neg-Y ative pole of the battery. The relay 75 opens contacts 76, 78, 82, and closes thecontacts 77, 79, 80, 81, and 83. This has the effect of extending the line wires 315, 316, 317 to the wires 90, 91, 92 respectively, and of connecting the driving magnet 71. of the synchronous circuit changer 70 in 'parallel' with the coils of the test relay 75. The potential of the test wire 92 is hereby lowered sufliciently to produce the busy condition of the trunks 90, 91, 92. Having gained connection with an idle final selector 105, the calling subscriber sends two series of impulses to the controlling relay 4 1 in the usual manner, and these impulses are transferred by any known system'of circuits to'the controlling magnets'125j, 126 of the final selector, so as to cause the movable contacts 320, 321 and 322' of the final selector to connect with the wanted subscribers line.

After the contacts 320, 321, 322 have been moved onto the contacts connected to the wanted subscribers line, the circuit of the test relay 97 is closed, a g. at 106, in the well known manner by the last change over impulse that ensues after the subscriber has sent the last series of selecting impulses,

tributing switch 101 of the wanted subscriber, to the positive pol of the battery.

The test relay 97 is then energized, and

closes the contacts 325, 326. By closing contact 325 a part of the test relay winding is short circuited, whereby the potential on the test wire 28 is lowered, and the busy condition of the wanted line established. By the closure of the contact 326 the circuit of the ringing relay 123 isclosed and this relay now causes the ringing machine to send out ringing current, which may be traced from the ringing through contact 4.00 of the relay 123, contact 101, contact 331, 329, 321, 391', (Figs. 41 and 1), 396, 26, 20, wanted subscriber 100, 21, 27, 39%, 392, 320, 330, 328, 402, ringing machine 327. When the called subscriber responds to the intermittent ringing current a ringing control relays-.03 is energized, and closes the contacts 333, 33 1. By closing the contact 333 the relay 12 1 isenergized by current flowing from the negative pole of the battery,contact 333, winding 124k, positive pole of the battery. Relay-12 1 is energized and closes a locking circuit for itself through contacts 407 and 323. It also opens contacts 335, 328, 336,

machine 327 331 and closes the contacts 337, 338, 339,

3&0. By opening the contacts 335' and 336 the driving electrofmagnets 125, 126 that move the movable contacts;320, 321, 322, are cut off. At theicontacts 328 and 331 the ringing current is cut off from the wanted line. By the closure of the contacts 337 and 339 the line 90 and 91 coming from the calling subscriber is extended to the line 329, 330 leading to the wanted subscriber. By theclosure of the contacts 338 341 are bridged across the line leading to and 340 the relays 127, 128 and the battery the wanted subscriber, and this subscriber now receives his battery supply through the relays 127, 128. When the wanted subscriber responded and caused the relay 103 to be energized, the contact 33% was closed and the eti'cct of this was to energize the metering relay 98 by a current flowing from the negative pole of the battery contact 334:, relay 98 to the positive pole of the battery. The relay 98 immediately closed a locking circuit for itself through the contact and by closing a contact 343 it prepared the meter circuit for closure, this closure taking place when the connection is broken down. The system is so arranged that on the wanted subscriber replacing his receiver the final selector and all the group selectors excepting the first group selector 102 are released. At theiirst group selector the replacing of the receiver by the wanted subscriber has only the effect of causing the synchronous circuit changer to take one step. In taking this one step the synchronous circuit changer at the first selector closes the meter circuit of the calling subscriber.

ll hen the calling subscriber replaces his receiver he causes all the selectors used in establishing a connection to be restored to their normal positions. lVhen the selectors are restored to their normal positions by the calling subscriber replacing his receiver, the circuit changers 50, and 93 at the group selectors and at the final selector step around in synchronism. In taking their first synchronous steps, the circuit changers 93 and 50 close the pairs of contacts 120, 121 and 56, 57 at the same instant, so that a circuit is closed, comprising the test wires extending through the chain of selectors used in establishing the connection and the calling subscribers meter. This circuit will be traced presently. After closing themeter circuit, the synchronous circuit changers when caused to move in response to the act of the calling subscriber in replacing his receiver, continue executing synchronous steps until each of them reaches and closes'a pair of contacts that control. the release magnets of the various selectors. The release magnets are then energized and the selectors re stored to their normal positions. It the called subscriber is the firstto replace his receiver all the synchronous circuit changers step around in the same way, as if the calling subscriber caused the release, "but the synchronous circuit changer of the first -selector only takes one-step in order to close the meter circuit, and then remains station ary until the calling subscriber also replaces his receiver. -The synchronous circuit changer of the first selector then steps forward and releases the first selector and the distributing switch belonging to the calling subscribizr. he object in arranging the release circuits in this manner is to force the subscriber to replace his receiver before he can establish a new connection. If the release circuits were so arranged as to cause the restoration of all the selectors the moment a called subscriber replaced his re ceiver, the calling subscriber could, without replacing his receiver, cause the first selector that was used for the last connection or any other free first selector to which he is connected by his distributing switch to make a new connection with another subscriber. F or the satisfactory working of the meter system forming the subject of this invention it is, however, important to force a calling subscriber to energize his line relay each time he makes a fresh call. This is accomplished by so arranging the circuits as to keep the movable contacts of the first selector on the line 315, 316, 317 used for the last connection until the calling subscriber replaces his receiver. If the calling'subscriber were now to attempt to make a new connection without replacing his receiver it is evident that he would obtain a wrong connection. All that is necessary to prevent a subscriber from making two calls in succession without replacing his receiver is to inform him that such wrong connections will be obtained if he fails to comply with the regulations. If it be assumed that the wanted subscriber replaces his receiver first, the restoration of the switches is initiated by the relays 127 128 at the final selector. The relay 128 is slow-acting, so that it keeps its contact 351 closed for a short time after the contact 352 is closed by the deenergization of the relay 127. This results in a cur rent flowing from the negative pole of the battery through 352, 351, releasing relay 353, to the positive pole of the battery. The relay 353 closes a locking circuit for itself through the contact 354, and by closing the contact 355 connects an interrupter to the test wire 92. This interrupter intermittently connects the negative pole of the battery to the test wire 92, and thus short circuits the magnets 357, 71 and 49 on the syn chronous circuit changers. These are thus deprived of current, and then enable the springs 163, 5 to drive forward their pawls so that their contact arms take a step forward.

The test relays 48 and 75 are short-circuited at the same time as the driving magnets 357, 71 and a9 of the synchronous cir cuit changers but these are arranged to let their armatures drop backslowly so that the relays will be reenergized by currents flowing from the positive pole of the battery through the relay 96 and resistance 318, the

moment the short-circuit is taken off the test wire 92 by the interrupter 356. Thus the short-circuits produced by the interrupter 356 only result in steps being taken by the circuit changers 93, 70 and 50, but do not cause the relays 48, 75 and 96 to let their plied to the metering wire 60 at the first selector, and a current flows from the nega tive pole of the battery through contact 343,

at the final selector, contacts 121, 120, busy test wire 92, movable contact 89, contact 80,

wire 317, movable contact 43, wire 358, contacts 57, 56, metering wire 60,wire 306, 25, contact 8, movable contact 3, wire 29, magnet 10 of the meter 9. It will be noted that the direct applications of the negative pole of the battery to the test wires 92, 317 by the interrupter 356 do not result in applications I of the negative pole to the metering wire 60, because at the moments that the interrupter 356applies the battery, the contacts 56 and 57 at the first selector are open, and these contacts can only be closed at a moment in which the interrupter 356 disconnects the negative pole of the battery from the test wires 92 and 317. When the prepared meter circuit is closed in the manner described above, the magnet 10 pulls over the lever 12 soias to cause the pawl 14 to engage a new tooth of themeter ratchet 15, and to cause the lower end of the lever 12 to move behind a catch 202. The meter will now register conversation as soon as the line relay of the calling subscriber is energized, and causes the current to flow through the magnet 11. This takes place after the calling subscriber has replaced his receiver, and then takes his receiver off the hook again in order to make a new call.

The releasing operation has been traced up to the point where the synchronous circuit changers 93,70 and 50 had stepped their arms forward one step, due to the negative pole of the battery having been applied to the test wire 92. By the further applications of the negative pole to the test wire 92 through the interrupter 356, only the synchronous circuit changers 93 and are aifected so as to continue stepping forward their contact arms. The synchronous circuit changer 50 does not continue its forward movement because it is not reenergized after it has taken its first step, the negative pole of the battery being disconnected from the contact 54, so that the circuits of the driving magnet 49 and of the test relay 48.

are definitely opened until the calling subscriber replaces his receiver, as will be presently described. Upon the second application of the negative pole of the battery .to

the test wire 92 by the interrupter 356, the

driving magnets of the synchronous circuit changers 93 and 70 are deprived of current a second time, so that each of them moves its contact arms another step. In taking this second step the circuit changers each close a pair of contacts at the same moment, the

circuit changer 93 closing the contacts 360, 361, and the circuit changer 70 closing the contacts 362, 363. By the closure of the contacts 361, 360, the release magnet 364 of the final selector is energized by a current flowing from the negative pole of the battery through 360, 361, 364 to the positivepole. The closure of the contacts 362, 363, results in the release magnet 84 of the second selector being energized by a current from battery through 363, 362, 84 to the positive pole of the battery.

When the calling subscriber replaces his receiver the relay 44 definitely lets its armature drop back, so that a slow acting relay 370 is deenergized, and closes a circuit for the release relay 371, which may be traced from the negative pole of the battery through contact 372, 456, wire 420, relay 371, oif-normal switch365, to the positive I pole of the battery. The release relay 371 'is energized and immediately closes a lookthe interrupter 376, so that the circuit changer takes a second step forward. In executing this step the movable contact 52 brushes past the contacts 58, 59 and closes the circuit of the release magnet 46, which may be traced from the negative pole of the battery through 59, 58, 61, 46 to the positive pole of the battery. The first selector will then be restored to its normal position. At the moment the release magnet 46 is energized this magnet opens the contact 307,

thus opening the circuit of the test relay 37 at the distributing switch. This relay re,- leases its armatures, and closes the contact 309. This results in a new circuit being established for the driving magnet 39 of the distributing switch,froin the negative pole through 309, contact 380, 301, driving net 39, interrupter 303, positive pole. The driving magnet then propels the arms 1, 2, 3 and 4 in a forward direction, until the distributing switch reaches its normal position, when the circuit of the driving magnet 39 will be opened at the contact 330. The synchronouscircuit changers 50,70, and 93 are so constructed that after havingxta ken two steps they are ready to produce another cycle of circuit changes of the same kind and sequence as in the previous cycle.

lit was assumed above that the releasing of the switches was started by the wanted subscriber. it will now be assumed that the calling subscriber first replaces his receiver.

a The eil'l'ect oi this is to deiinergize the relay l t in a manner alread described, so that the slow-acting relay 370 also deenergizes, and a. circuit is closed from the negative pole through the contacts 372, 456, wire 420 and relay 371 to the positive pole. The relay 371 closes a locking circuit for itself through the contacts 374 and 365. By the contact 375, the releasing relay 371 connects the interrupter 376 to the wire 377, and as the test relay 48 still has its armature attracted, the interrupter 376 will also be connected through the contacts 64 and 65 to the test wire 317. it will also be connected through the contacts 64 and 67 to the test relay @n each application of the negative pole ol the battery to the test wire 317, the test relays a8, 75 and the driving magnets ll), 71 and 357 01 the circuit changers will be short-circuited. As the test relays allow their armatures to retract rather slowly they will. keep their arinatures energized. in the inter als between the shortcircuitings produced by the interrupter 376, but the driving magnets 49, 71 and. 357 will release their armatures and cause the movable arms of the circuit changers to step forward. As the circuits of the test relay 48 and of the driving magnet 49 at the first selector are new kept closed at the contact through the armature 378 of the release relay 371, the synchronous circuit changer will participate in the synchronous movements of the circuit not only in taking its firststep, but also in taking its second step. In taking their first steps the circuit changers 93 and 50 close the meter circuit through the pairs of contacts 120, 19.1 and 56, 57 in a manner al ready described. In taking their second steps the synchronous circuit changers 50, and 03 close the release circuits of their respective release magnets L6, 84 and 364: in the manner described above. The circuit of the test relay 37 of the distributing switch 101 is also opened at the contact 307,

so that the distributing switch is also caused to return to its normal position.

The events which take place in case a busy subscriber is wanted for a long distance conversation will now be C escribed.

If the calling subscriber is Wanted, all the selectors are released by the long distance operator, except the distributing switch 101 of the calling subscriber. The long distance operator selects the line by means of a selector 103, and finding the wanted subscriber busy he closes a contact 380,which has changers 70 and 93,

the effect of energizing a relay 4:? in the first selector, by a current flowing from the ncgative pole of the battery through all, 22- 5, 4-, 19, as, 31, 380 to the positive pole. :elay a7 is kept energized; it opens the contacts 68 and 69, at the same time closing contacts 381, 382, 383 and 331. By the closure of the contact 382 the release relay 37L is energized by a current flowing from the negative pole of the battery through 382, 371, to the positive pole. The release relay 371 then closes its contacts 37 375, 3'78 and 379, and causes the selectors 102, 104, 105 to is re leased in a manner already described. The restoration of the distributing switch 101 to its normal position is prevented by the con tact 30? 01" the release magnet being shortcircuited by the contact A conversation may now be carried on over the wires 3:2 and 33 and over the wires 17, 13 leading from the long distance exchange to the local oliice. lVhen the long distance conversation is finished, the calling subscriber, without replacing his receiver, sets up tie local connection again through the switches 102, 1021, 105, and as his line relay 38 is not energized again in making a new connection with the subscriber from whom he was previously disconnected, the previous local call will not be registered until the calling subscriber has finished the desired local conversation and.

reenergizes his line relay 38 in making another call. When the long distance ere change disconnect-s, relay 47 is deenergized and the relay is. is reconnected to the trunk 22, 23, its armature being kept att *acted by the current flowing from the battery 4.50 to the calling subscriber. Should the calling subscriber decide to abandon the connection which he had previously made to another local subscriber, he will replace his receiver and open his line loop, thus deenergizing the relay 4%. The armature of the relay i l, by opening the contact 454: deenergiaes the relay 370. This slow-acting relay then allows its armature to retract so as to open the contact 455 and close contact 4-56. The open ing of the contact causes the deiinergi- Zation of a relay 41:32, which is also slow acting. Before the relay has time to open its armature contact, a circuit i closed from the negative pole of thebattery through contacts 372, d563, 457, wire 4e58, contact 459 (which has a normal contact that is kept closed by the synchronous circuit changer Whenever this is in its normal position, but which is opened whenever the circuit changer is in any other position), wired-53, release magnet 46, positive pole of the battery. The energization of the release magnet 46 causes the opening of the contact 30? and the deenergization oi the test relay 3? at the distributing switch. The deenergization of the test relay of the distributing switch re sults in the distributing switch being stepped into its normal position .in the manner already described, If the wanted subscriber is disconnected from the calling subscriber by the long distance oifice, the calling subscriber waits until the long distance conversation is finished, and is then immediately reconnected to the wanted subsciber. As

all the subscribers in the exchange are provided with similar apparatus it may be assumed for the moment that the station 100 is that of the wanted subscriber, and that another similar station is connected to it through selectors similar to 102, 104;, 105. The long distance exchange 104 connects to the wanted subscriber through a selector 103, and on finding the wanted station busy closes the contact 380. In this case the closing of the contact 380 does not aiiect any relay 47 in a first selector, because the arms 1, 2, 3, 1 of the distributing switch are in a normal position and the only eii'ect produced by closing the contact 380 is to energize a relay 390. The relay 390-opens the contacts 393, 394C and closes contacts 395, 396, thus disconnecting thewires 391, 392 coming from the calling subscriber from the wires 26, 27, leading to the called subscriber, and connects the wires 391, 392 to a tone-giving device 397. The device 397 causes a sound to be propagated over the wires 391, 392 to the calling subscriber, thus notifying him of the disconnection, due to a. long distance conversation. The tone-giving device 397 does not permanently open the circuit of the relays 127, 128 at the final selector, but allows intermittent current to fiow through these relays so that the final selector release circuit is not closed. The calling subscriber then Waits until the long distance conversation is finished, which will generally be in the space of two or three minutes, when the contact 380 at the long distance exchange is opened, and the relay 390 deenergized so as to reestablish the connection between the calling local subscriber and the wanted local subscriber over the wires 391, 392 and 26, 27. At the finish of the conversation the calling and called local subscribers replace their receivers and cause the selectors to be restored to their normal positions in the manner already described above. Any subsequentremoval of the receivers from the switchhooks at the local stations will cause the energization of the line relay 38, and the closure of the circuit through the electromagnet 11 of the meter 9 of the particular calling station, so that if a successful call had previously been made by the calling station, this previous successful call will be recorded by the meter 9.

Although I have referred in my above specification to the exchanges for local and long distance connections as local exchange and long distance exchange, I desire it to be understood that Ido not wish to be limited by these specific terms, for the functions described in connection with the long distance exchange might just as well be performed by some other kind of special exchange. 7

Obviously in the practice of my invention many alterations and modifications may be made, both in the circuit arrangement and the mechanicalstructure oi the device with out departing from the spirit and scope of the invention, thus, for example, the several batteries shown herein as separate and distinct, may be one and the same. Other like modifications may be made. I, therefore, do not wish to be limited to the specific matter disclosed, but aim to cover by the terms of the appended claims all such alterations and modifications.

I claim:

1. In a telephone system, the combination with a plurality of calling and called lines, of selector and connector switches adapted to automatically interconnect said lines, conversation recorders, preparatory circuits extending through said switches for controlling the preliminary action of said recorders, said preparatory circuits being controlled by-said called lines, and supplementary circuits for controlling the final action of said recorders to effect registration, said supplementary circuits being controlled by sald calling lines.

'2. In a telephone system the combination with a plurality of calling and called lines,

of selector and connector switches adapted to automatically interconnect said lines, COIIVQISfltlOIlCOIlIltBFS, relays at said connector switches circuits extendedto said called lines by said switches and including said relays, preparatory circuits controlling .a preliminary counting action of said counters and controlled by said relays, line relays associated with said calling lines, and supplementary circuits for controlling the final action of said counters to effect registration, said supplementary circuits being closed by said line relays.

3. In a telephone system, the combination with a plurality of calling and called lines, of electro-1nagnetically controlled selectors and connectors adapted for interconnecting said lines, conversation counters, relays at said connectors, circuits extended to said called lines by said connectors and includmg said relays, preparatory circuits controlling a. preliminary counting action of the said counters and controlled by sald relays, hne relays associated with said calling lines, and supplementary circuits for controlling the final action of the said counters to effect registration, said supplementary circuits being closed by said line relays.

4. In a telephone system, in combination, a plurality of lines, selector and connector switches adapted to automatically interconnect saidlines, conversation counters, a propelling. device in each of saidcounters, electromagnetic means associated with the connector for controlling the initial move ment ofsaid propelling device, and line relays associated with the calling line to finally operate said propelling device and effect registration.

5. In a telephone system, in combination,

a plurality-of lines, selector and connector swltches adapted to interconnect said llnes, conversatlon counters, means assoclated with said lines for causing the operation of" said switches, electromagnetic means associated wlth said connectors to impart an initial operation to said conversation counters after the called subscriber answers, and hue relays, associated with said calling lines for subsequently completing the action of said counters to effect registration 6. In a telephone system, in combination, a plurality of lines, selector and connector switches adapted to automatically interconnect said lines, conversation recorders, line relays associated "with said lines, preparatory circuits controlling the initial has beenassociat'ed therewith, a relay asso ciate'd'with one of said switches that is energized in a circuit including the called line, electro-magnetically controlled device for closing said normally/opened contacts, said device being controlled by said relay, a

. recorder control relay, preparatory circuits for controlling a preliminary recording action of said recorder and closed by said recorder control relay, a line relay 'asso ciated with the said calling line, andsupplementarycircuits for controlling the final action of said recorders to effect registrar tion, said supplementary circuits being closed by said line relay. Q i g a I 8. In a telephone system, in combination, a plurality of calling and called lines, conversation recorders, electro-magnetically controlled selectors and connectors for associating a said calling line with a called line,

normally opened contacts in said connectors for maintaining an interruption betweena calling line and a called line after they. have been associatedwith each otherby said Solectors and said connectors,-a relay associated with each connector that is energized. 1n a circuit lncludmg the said called line,

a second relay associated with said connector for closing the said normally opened contacts and controlled by a said first relay, a recorder control relay, preparatory circuits controlling the preliminary recording action of the said recorders and closed by said recorder control relays, line relays associated with said calling lines, and supplementary circuits controlling the final action of said recorders to effect registration, said supplementary circuits being closed by said line relays.

9. In a telephone system, in combination, a plurality of calling and called lines, conversation recorders, electro-magnetically controlledselecto-rs and connectors, talking con tacts in said selectors and connectors for associating a said calling line with a said called line, normally openedcontacts at said connectors for malntaining an lnterruption between a calling line and a called line after they have been associated with each-other by some of said selectors and one of said connectors, a relay associated with each of said connectors that is energized by a current flowing over a called line, a second re- I lay at a said connector for closing the said normally opened contacts and controlled by a said first relay, test contacts in said selectors and connectors, a recorder control relay, preparatory circuits for controlling the preliminary recording action of said record ers and closed by said recorder control relays, said preparatory circuits includinga said test contact, a line relay associated with said calling lines, and supplementary circuits for controlling the final action of said recorders to effect registration, said supplementary circuits being closed by said line relays. 7

10. In a telephone system, in combination,

a "plurality of calling and called lines, electic-magnetically controlled selectors and connectors for associating a said calling line with a saidcalled line, synchronously acting circuit changers at said selectors and connectors, conversation counters, relays at said connectors, circuits extended to said called lines by said connectors and including said relays, preparatory circuits for controlling the preliminary counting action of said counters and controlled by said relays, said preparatory circuits including parts of the saidsynchronously acting circuit changers,

line relays associated with said calling lines, and supplementary circuits controlling the final action of said counters to effect registration, :said supplementary circuits being closed by said line relays.

11'. In a telephone system, in combination, a plurality of calling and called lines, elect re-magnetically controlled selectors and connectors, trunks extending between said seleca plurality of' callingand called lines, ,elco.

torsfand connectors, said trunks eachicontaim 7 ing talking Wires anda test'wire, saidselectors and connectors having talk ng contacts .for

extending a'calling line toa called line, said selectors havlng also test contacts for connecting uto test avires o isaid vtrunks, restoring magnets'for restoring sa d selectors and connectors to the normal positions, conversation counters, relays at I said connectors,

Circuits ende to said z kd lin s by sea e nne or ndincledl e';sa dvre yanrenarr atory circuitsior controll ngthe prelnnlnary counting I action of said vcounters and controlled by said -relays said preparatory circnitsand the circuits ofthe said restoring magnets being closed through chased test wires, line relays associated with said calling lines, and supplementary circuits for controlling the final action otsaidcounters to effect registration, said supplementary circuits beingclosedby said line relays.

I 12.1 Ina telephone system, in combinaticn,

. tire-magnetically controlled switches, oneof said switches'being fused in establishing ,a connection between a call ng 11116 and a calledline, a restoring magnetfor restoring.

such switch, restoring circuit for controlling said magnet, saldrestoringclrcu t be ng controlled by the calling line, a conversation counter associated withsaidcalllnghne,

a preparatory circuit controlling the preliminary action of said counter, said preparatory circuit being controlled by .the calledline, anda supplementary circuit controlling the final action of saidcou'nter to f c egi t n, Said, pp eme a y i cuit being controlled by the calling line relay." 7 s v K 13. Ina telephone system, in combination,

a plurality of calling and called lines, electro-magnetically controlled selectors and connectors, one of sa d selectors 1n cooperatlon wlth one of said connectors being adapted to associate. a calling line lwithfacuit being controlled by saidcalled line, and

a supplementary circuit controlling theflfinal action of said counter to effect registration, said supplementary circuit being controlled by the calling line' r'elay. v 1 14 In a telephone system,.the combination with subscribers lines, of selector and connector switchesfor establishing connection between said lines, conversation recorders, means-t0 reflect an n ma creati n pfs id recorders when the calling subscriber disrecorder to register the call when the calling subscriber initiates tl e next call.

15. Ina telephone system, in combination, a local exchange, another exchange, a plurality of called and calling lines connected to the local exchange, electro-magnetically coontrolled switches at the local exchange, one of said switches being adapted forassociating V a calling line with a called line, a restoring magnet for restoring said switch, a restorlng circuit for controlling said magnet, said re storing circnit being controlled by the cal ing and called line, and by thesaid other exchange, a conversation counter associated with said calling line, a preparatory circuit 7 connects, and: means to finally operate said controlling the preliminary action of said counter said preparatory circuit beingcontrolled bythe called line,anda supplementary circnitcontrolling the finalaction of said counter, said supplementary circuit being controlled by the calling line. ,7 V

16. In a telephone system, the combination with subscribers lines, of selector and corn nector switchesifor establishing connection between lines, conversation recorders,

means operable to give saidrecorders an initial actuation during therdependency ofthe call, and means to finally actuate said recorder to register the connection when the calling subscriber initiates the next call.

17. In a telephonesystem the combination with subscribers lines,;of selector and connector switches for establishing connection between said lines, conversation recorders, a line relay associated with each line,tmeans controlled by the callingsubscriber to initially-operate said recorder after the called subscriber V responds, said recorder being finally operated" to register the connection upon the actuation of the line relay whenthe calling subscriber initiates the next call.

18. In a telephone system, in combination, a localexchange, another exchange, aplurality of calling and called lines connected to the localexchange, electro-magnetically con trolledswitches atthe local exchange, one of said switches being used in establishing a connection between a calling line and a called line, arestoringmagnetfor restoring said switch, an electromagnetic device associated with the calledline, said device be as, I

ing controlled by thesaid other, exchange 7 and being adapted to disconnect thecalling line from the called line, a restoring circuit being controlled only by the calling line, a conversation counter associatedWith-the calling line, a preparatory circuit controlling the preliminary action of said counter, said preparatory circuit being controlled by the called line, anda supplementary circuit controlling the final action of said counter,said supplementary circuit being controlled by *thecalling line, r

19. In a telephone system, in combination, a local exchange, another exchange, a plurality of calling and called lines connected to the local exchange, electro-magnetically controlled switches at the local exchange, one of said switches being 'used in establishing a connection between a calling line and a calledlinc, a restoring magnet for restoring said switch, a signaling device, an electromagnetic device associated With a called line, said deizice being controlled by the said 7 other exchange and being adapted to disconnect the calling line from the called line and to'connect the said signaling device to the calling line, a restoringcircuit for controlling said restoring magnet, said restormg cuit controlling the final action of said counter, said supplementary circuit being controlled by the calling line.

In Witness whereof, I hereunto subscribe my name this 12th day of September A. D.

FRITZ ALDENDORFF. Witnesses G. DE LERTZ, N. ADAMS.

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